SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8b098f11474630fd6c885dd164f156afb9b7f5847371f1a516594955665f816' 
  AND token = 'wEPYMGejM7aodZHI0Y3lSCFw1T09/ZgmSmVCNFhIo30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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