SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db2452812d3fb142f5e90a9da5da140d004348d53f9e50e743d89cc855636080' 
  AND token = 'GhhP1WKP/NLOjglkLpn1T1+EMJUp/ml2hjWwZWAMJYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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