SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b6f90f72e13a02bd4e77d641ad2126385d6bb5dfe348c4ab1d6fde5453c30f8' 
  AND token = 'zLkBKXqigNkcV3HVyjfEyVO/rKBLstVgqBJB7gPaqQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}