SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5757287d1dc84a3216d357cae1a70d8f76261513409ae7bf9f3dcaf430c90dd0' 
  AND token = 'UAVkQMMMYI0q3PQpCyD0/r4fPbRGYEpBlglwrARD3Lg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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