SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3307ed6a613d49c311561a2da1ee75118a06bd482a5afc5e0c6433359e5ca8f3' 
  AND token = 'VTebrSmiqrDW+UO72VBg3Nvh/UUBbGM7C37LS+QWtm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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