SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afbdbfefed833de7a08287d3d70bae51974cff8aba0c2910addcad61da69a10b' 
  AND token = 'FMKeQhsQVtHoTjXqphM6z00ecEddQw20WrygPZnUUvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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