SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb09fd8fc3bde2af510c221d0199ca972dfdebf4d2b09b17c061b242e056e543' 
  AND token = 'IDKpi7XKMuj15mJvHbqr2CVbVUkuoI+UI1Awz8c25ws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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