SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97d51c85491c40eec83acacd6a7b381b30e56437031a6b9fb2075357e7297ddf' 
  AND token = 'gP3++Fgfo5MCDbPfEhmszi/MBIHF2gLL71BD6kNDu2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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