SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '101d515d5f7d158bbfc6e3874080c0f8269711b36f2eca80aaae1a0217fbcfac' 
  AND token = '6zRTdbcfCTFjL0LhSbkGQDIgAFIv538ivxsazwbl6/0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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