SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44362de36544494141d06b499644ea9df4265c25a08775aa38507a68cb71f4c5' 
  AND token = 'IT6ilcvPyVSLZIFdUq2bxcLN5Mq0k2KXhUwqjQVruik=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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