SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5811128a5fb1029b692ba135ee71fa89b79d3e92b21caf65a6915cf61b15751d' 
  AND token = '30iAJwqoxvHaDbo87HSopIMNYt7NXa7b+sprJ5SKEcM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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