SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6bc1927b1112b7a751a7754b539b941a69c726cc18ead090e36ae9ea63749b05' 
  AND token = 'DUVXzMlahWvKDVj3CkaPczdIv22AuNG6p7fCJylm72Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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