SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91b2aa56e6f0e3471bbfeb2abe9ab028b0d571e9456b18bb8eb04f63c163d180' 
  AND token = 'nOAhQhihSJyOyHaNm5ElYGjPy40AGcsQpgFIP1FGMYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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