SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad7818b2d8da44444c861e80d211443e534d948e63c4befa391fa5ff90562db6' 
  AND token = 'j1U5zC3IBs+5aKELRIdlbXL7mBWwJs24np26vG7HUjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}