SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2bc91b35dae547661afcbe5a4ddbeb63418f6b0fad766dece3971c65a2e3d77' 
  AND token = 'BICNXeLZTkI5WZ2d7PHn4iiKVhJA0WHCKrV4AScxSLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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