SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14a988267bffcdc4f54f74751f63db831f032fdffcdcd71091cc173f6c1420b8' 
  AND token = 'uJo3QIAJ+k2iDSoN5qSvSh8eCVZsU/DOmQTstjQqmi8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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