SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75e6975dba97750a54d02a8986de2fb135cfb0c06683a78942d7dc334c3a50e1' 
  AND token = 'OQzDB9pmd3H3EjXW5O+CaDAzs+yUlXoEWlqJSSBVniY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}