SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6301bcdaccedeb06f754d766583856987c0d9a4336b1058ca529f021838ec97' 
  AND token = 'GXgH9Q7y1dnCcmT6SHZ5IIcsd/q0yhqfay8OMDMvcvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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