SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '538a8b7e7c75885d652b49083223a1a7584ed9c608084dac510d6362d8e22f0e' 
  AND token = 'Wmh0DDzlS38BAFEtERx6vP5Kq/tfQcrxWE1VZv/X+c8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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