SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b17fd77a3643da4b0992243b6ddec340c4a558a8666c14cb93b551d77fd8106' 
  AND token = 'NYzUbzxN0A2JTH7Deb5+JZf7xXc4jHA3UrVSFr3n/2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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