SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a958ba9f79acb8159e8c3c1cec53550c5e260cf6e2116e1e581b534abbffa595' 
  AND token = 'fIncvLTqNFOAZD1wo+L7rrODAqtsxekzuCBQPsaB404=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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