SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2273bc092ecd7f8ccda20ec2ef24238ee005a6ace50d728259da557eb2397b89' 
  AND token = '4eBmxDGF8RM/bSlJKZEM+uPMHk81Vh4zwwF+zM44eyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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