SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0a1f39ed686529747bd18e1b597edcd4b6d09746203713d644149053f0a5c8e' 
  AND token = 'cCbmg6ESThP1Zb8kZbgEpl4v4vZLdGhwoNWdvevXRog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}