SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f597f5572d2021dba383be71278873a4aff97b65c88360b40790fa7d8283459d' 
  AND token = 'Af671zJmu+ab8ldgXspCX6xIR+yqsGPmBYM/Xl8mE4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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