SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97d067d94c66a417c298394f11df672a0e1edc110994023a749347c19738ac13' 
  AND token = '1BnmOvZlgEu8RbWiPYdxHFkV5cJDfewESgo8T98eOQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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