SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ef4cef39f68d477107147ebf413ee9ec7f2f217a0a707760390475db0a6508c' 
  AND token = '+z8a2GN5mW2vhw8GBHSxNVHf46qzpKiUdhLjJB96KfA=' 
  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"
    }
  }
}