SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f1304021442e5ec2d091381e7310447f7f649394d821b70308ca51b3fb029f5' 
  AND token = 'FYmBjtHzZ3tromT+CXf7nNcWxYJmjOFqwzFLKJONmpU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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