SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ca3f553c860e4657aa6fc9c6249e06186123689fafc74b97d54dd4c42c0733d' 
  AND token = 'bRcDbgFrA+VftgbHzwdcejkLAL6UzdKnTfcuAU1vmuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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