SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b19ad6af0d2301fca0a285aa69b0054306f51972b95fda112db4674b2aa0ec5' 
  AND token = 'RwAn1XgMEUijJc6Qbb1SypKIlOQUApGkTzWy+66HESg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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