SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64ef34b7b2888855a3125fa1d13d8be6b3c592770101752a509278aab40d2a61' 
  AND token = 'BWhzPd+hr7zB4AlHZuBOmpOANbJHEMskVSmv0h+io4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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