SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e2d50951d2c4dba02d8f20713fac48530fab8901442d1c600440cb52f9b36ff' 
  AND token = 'vISZscY/9uZflnGG4xEaIH6/Bv+mmYt6qk+n4hVxsJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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