SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fda52e2c412ffc0f933b1bfaed8fe5aa6bef9eb6431237f523d24d2e1e8c0ea1' 
  AND token = 'Vcl5Q45ySptpcSPR4w6II4hDxr1AY6yXgeUVm2OZpoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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