SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4dbc811ff9b3d4435b97883a8d45f22bd6c5b8ae0352feffea8226029ea8205' 
  AND token = '7+k1OH8weIP66uQ1z7ZagYZGiRzN2gkz11+jrvgbu0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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