SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a4c65a8cea99ccfc27bceebc20e5ffefbb569611241285b972e8a6033bfc70a' 
  AND token = 'av1wDush+ohSgxATEVdz1JkVrCTNXojdO6pUPExYxN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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