SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e3ea4b895a0599d496829664caf95210c176d5c61123a1b895c86b949356866' 
  AND token = 'eDNYPIH1LDLdQGqW6AkPHsBrHRIfrk8p+ReYRZBrXGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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