SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20fa06bb5c0bc15db168536d56625b1cb084087e7456e389183db3c7cc2fa333' 
  AND token = 'gnNEIppqfWvJhmEwwrgzMpySB/KewPPfXDJ+7W/GxSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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