SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb629b3afc16471e9d0eee0ae767b9fd888e43e718fabd609bd72ffa6f0b7c30' 
  AND token = 'aj1wFAypnxv5eYLFrxaHUfJOUfD1hOnf9ilranUvwEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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