SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b2856ce161cde55ed5d32e241598e9bcd037f6e1e24ea9e12a78a199dfc93745' 
  AND token = 'akHZMA/X7G4MHNetDoVFljws4mj37wUZfn/1T5xYC70=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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