SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '234023b5cf007fd2b65907614d311fa38d037b4fecc3403606079cd2d1ed34df' 
  AND token = '7PeQbwVZwluRvHzvqAB9kHmXj2rHDUKmFGfTsPpe9tk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00064

JSON explain

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