SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a81e8658c67cf630903a55aa660fe673baff5b0c106fd7ccb1879a4cead31b8a' 
  AND token = 'IuVCNjtCaubLnuzhGy8d3EGNhkmn9B0Q94aExfkfC0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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