SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e785c6a60c6171c300c3e0e52befa54ed4bc8c4d68c70cae766cf84342dd65f2' 
  AND token = '2BjBm1N9n2sFMuf5SzdgjF3ya2nskbhMsRunfJj4q9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}