SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad883710bf1ecdb0776c08beb8efad781dc1aa6c0c8c6fa10e38af50a918f0a0' 
  AND token = 'hzIYpNUpucKR/aSlkY8Ad4NwOU/VRS5aw3K7XRiDsg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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