SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5249849df9627487eef34b67489fb97c060c9d60275c3e5be4e123e75d44e373' 
  AND token = '1+Ph5yd4YTXBunCMlV1SHAgRrZJpxtKq4DmY4qlcebY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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