SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55aba8f453170aeab08b42ddadfcc65c87bf991174888f83657df2e4b6a4cf21' 
  AND token = '53rrSU1U+VsuipROnG1QICjiKR+MRFjiUn2Y+uWwDIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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