SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '691f374bdad4fafbbcf647d01fc2ce171ae685b13fa3d231aaa2b43a9dccaf6b' 
  AND token = 'yBuqBmC5RyxKkkAU7Uo7rmMupeF7qHYCPP9MOSCnm3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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