SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '587ff2798e46162371bee0ee71fd9c7973597c24867d799d6383ffadf3644194' 
  AND token = 'Ggfuv+iUvIn1EYG6D6zASAFF9s69719Blx7WgKR7fhI=' 
  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"
    }
  }
}