SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ee1efbbc8c7925d70d6271077259c2616348c83bf265c6b9132a26f431f4934' 
  AND token = 'L/CSK0ezTWAKIk8miRzCZoiLCNsulPq+hgRPF6eMrIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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