SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '835446d940261230c2c6d0916c1986f3ef7a6129c4d176e2301815ad632616b2' 
  AND token = 'pV9rLiAOgtPFJuqpDuCGXB3gLaZKE4eTbjRvkzvIyaU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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