SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98075c5cb915ebd9136c57a78b51d93e164f460df561013b812fbee6db2e4cdf' 
  AND token = 'pM8am6VKtrhqOW/tlI29NMmfsjChaYRjh4xUing75qk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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