SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c713bd806854c91dd651df7789783fd4f68df80b05d6ae4232783976d443502b' 
  AND token = 'fLhaYAdcmuPAznbUo3JIlsorqqMbsx86b0T0mPyBoog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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