SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec79ad27740f8ae6efa657daba526384cd4ffeba129bf4c1c1eecd7fc600ea70' 
  AND token = 'A/EuoSCTBdmeCCNHiyVKpMzWiRw7edBY5+0kGwJN/RM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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