SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef67d6e2474d804f5acedb8d92b757b5d451855477d3d03d61698f1dcd12ab18' 
  AND token = 'rFA9kPFlsAARvaRpBVOC3i+Cs2v8Wz64RetZo//95v0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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