SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd31d7eeaf64802d21d78561a1a8d2a4b3479492e2b66f71d84d5260947af265d' 
  AND token = 'CipVqVundtsc2SAJxG4eocf90Xe1hQlTAlyj9usJzag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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