SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0199f35440fd09fdf9d5290e4267bec2dd743a91323f47874037ecc50b24fd8' 
  AND token = 'elzo2ln0Yngt5by0ng3ARTSvEPJiUUnZ1iBbYK1SV9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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