SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8924474d2a74f398b50c11ec4d73622fb23566a2ca2671e30a9a3d1ea1264b99' 
  AND token = '+lqClM0FhqHePjZCd/RBXF8JESVuhykCvvl98zYya6c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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