SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6e5bbe6512bb1c3b48be9b1413d99242effccd7068ecbc288a16ae527d7108c' 
  AND token = '5nY1k/Ri0a78oA+l0K0N/DG/FlpMV7zrznG0h1aEgyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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