SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b74a39c930cc7def9416340dbc0b72cead3476c31f6f0ff4074b41b3499aeef' 
  AND token = 'aZlYA8roMoOsA2wzYwWiNOp8UFvN57jmEI53ANNnKhc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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