SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '311c4559fcc4c66ba3668c73bf7baa9e9de5deaec4bbcac5445f19747d19e523' 
  AND token = 'lvQgGO/2lICHjt4eMcKJsFQN2xe3XFcd6DFNbyYxarM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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